REVIEW ARTICLE Phytochemistry and medicinal properties of Psidium guajava L. leaves: A review Vajira P. Bulugahapitiya * , Shanthirasekaram Kokilananthan, Harshi Manawadu & Chinthaka Sanath Gangabadage Department of Chemistry, University of Ruhuna, Matara 81000, Sri Lanka *Email: vajira@chem.ruh.ac.lk ARTIC LE HISTORY Received: 15 June 2021 Accepted: 26 July 2021 Available online: 23 October 2021 KEYWORDS Psidium guajava Phytochemistry Pharmacological actvity Chemical compositons ABSTRACT Psidium guajava L. (Myrtaceae), also known as guava, is a medicinal tree natve to tropical America that has been introduced and is widely available in many countries. Almost all plant parts of P. guajava have a long history of being used to treat a variety of ailments, in additon to applicatons as foods. Guava leaves are used as both medicine and food purposes, and there are numerous scientfc reports on their medicinal uses, chemical compositon and pharmacological propertes. Cancer, blood pressure, diarrhea, bowel irregularites, diabetes, cough, cold, constpaton, dysentery, scurvy, weight loss, improves skins tonicity are some of the diseases treated with guava leaves. Polyphenols, favonoids, saponins, tannins, terpenoids, glycosides, favones, cardiac glycosides, cardenolides, phlobatanins, steroids and other classes of bioactve compounds have been identfed from the leaves. The primary chemical consttuents of guava leaves are phenolic compounds, iso-favonoids, gallic acid, catechin, quercetn, epicathechin, rutn, naringenin, kaempferol, caryophyllene oxide, p-selinene etc. Several studies have demonstrated its pharmacological actvites including antoxidant, antmicrobial, antdiabetc, anttumor, antcancer, antdiarrheal, healing, cytotoxic, hepatoprotectve, ant- infammatory, antmalarial/ ant-plasmodial, dental plaque, antglycatve and many more. This review is aimed on compiling all the literature reported on pharmacological actvites and phytochemical compositons of guava leaves as a support to the scientfc community for further studies and to provide scientfc data to validate its traditonal uses. Abbreviations ABTS: 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid, ADM: Adriamycin, CH3Cl: Chloroform, CT: Cholera toxin, CUPRAC: Cupric ions (Cu 2+ ) reducing ability, DPPH: 1,1-diphenyl-2-picrylhydrazyl radical, ELISA: Enzyme-linked immunosorbent assay, ELISPOT: enzyme-linked immune spot, EtOH: Ethanol, FRAP: Ferric ion reducing antioxidant power, FC: Flavonoid content, GAE: Garlic acid equivalents, IL-6: Interleukin-6, LDH: Lactate dehydrogenase, LT: Labile toxin, MeOH: Methanol, MIC: Minimum inhibitory concentration, Min: Minutes, MTT: 3-(4,5- Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide, OGTT: Oral glucose tolerance test, ORS: Oral rehydration saline, PGE2: Prostaglandin E2, PMA: Phorbol myristate acetate, PSA: Prostate specific antigen, PTP1B: Protein tyrosine phosphatase 1B, QE: Quercetin equivalents, ST: Stable toxin, TBARS: Thiobarbituric acid reactive substances, TEs: Trolox equivalents, TPC: Total phenolic content, Tr: T regulatory. Background Psidium guajava L. also known as guava, is a fruit- bearing tree from the Myrtaceae family that is native to tropical America but is now grown throughout the tropics (1). P. guajava belongs to the Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Subclass: Rosidae Order: Myrtales Family: Myrtaceae Subfamily: Myrtoideae The bark is reddish brown, thin, smooth and flaky. The roots are extensive but only superficial. The fruit has a strong, sweet, musky odor and can be round, ovoid, or pear-shaped. The leaves are the most used © Bulugahapitya et al (2021). This is an open-access artcle distributed under the terms of the Creatve Commons Atributon License, which permits unrestricted use, distributon and reproducton in any medium, provided the original author and source are credited (htps://creatvecommons.org/licenses/by/4.0/). PLANT SCIENCE TODAY, 2021 Vol 8(4): 963–971 https://doi.org/10.14719/pst.2021.8.4.1334 ISSN 2348-1900 (online) HORIZON e-Publishing Group